Now is there a way I can nest/embed the linear combination into the model statement so I do not have to calculate the estimates of income and distance manually?
Of course my model has many many variables so I want to find a way to let SAS spit those out for me.
What I understood from your description is that you want to use a linear combination of income and distance as a single variable (demographics) in the logistic regression model for choice.
I think you could use the variance components analysis to create your demographics variable. Then it can be plugged into your choice model. With ODS and a bit of macro programming this can be automated.